1. Field of the Invention
The present invention relates to a pipe joint which can be easily detached from and attached to pipes, and more particularly, to a pipe joint which can be easily detached from and attached to pipes, instead of a conventional a flange joint using a number of bolts, to thus remarkably reduce a manufacturing cost of the pipe joint.
2. Description of the Related Art
Detachable screw or flange joints and non-detachable weld joints are applied to pipe joints.
In the case that various kinds of devices such as valves, pumps, filters and heat exchangers which are connected in the middle of pipes, should be replaced with new ones in an operational process, screw joints and flange joints which can be detached from and attached to pipes are applied as pipe joints. Since it is difficult to apply screw joints to the medium-size or large-size pipes, flange joints which are fixedly connected using a number of bolts are applied thereto.
In the case of the flange joints, flanges having a predetermined width are formed along the circumferential direction at the ends of the pipes, respectively, and a packing is inserted at a joint portion where the pipes are connected. Then, the flanges are coupled using a number of bolts. Accordingly, the width of the respective flanges should be increased so that bolts can be fitted and tightened at the end of the pipes, to thus cause weight of the piping materials to be increased. In addition, since a number of bolt holes should be mechanically worked in the flanges, a productivity of the flange joints is reduced and a manufacturing cost thereof is increased. Further, since a number of bolts should be coupled at the time of connecting pipes using flange joints, and tightened uniformly at the time of tightening the bolts, a workability of connecting pipes is remarkably lowered. Further, when the flange joints are disassembled and assembled, bolts may be worn or damaged to thus make it difficult to connect pipes using the flange joints.
In order to improve the conventional problems of the flange joints, a connection tube which can be fixedly connected with pipes while maintaining air-tightness of a flange portion without using coupling bolts has been proposed. Here, a number of O-ring fitters are formed at one side of the connect ion tube, and a fixing portion into which one O-ring is fitted is formed at the other side thereof. The number of O-ring fitters which are formed at one side of the connection tube, are inserted into one member and the fixing portion which is formed at the other side of the connection tube and the flange portion which is formed in the other member are fixed by means of clips at the state where the former faces the latter. However, such a connection tube may be loosened and separated from the pipes if it is highly pressurized, to thereby make fluid leak from the pipes.
In addition, there has been proposed a conventional pipe joint where a locking protrusion and a latch protrusion are formed at both ends of a connection plate having a concave groove into which a flange portion formed at the leading end of a connection tube is simultaneously fitted, so that the locking protrusion is locked by the latch protrusion. However, such a conventional pipe joint is not influenced by a low pressure of fluid flowing in the pipe, but may be deformed by a high pressure thereof to thereby make fluid leak from the pipes.
Besides, a clamp type connection unit which is connected with pipes at the state where flanges formed at the ends of the pipes are fitted with a concave portion of a connection plate of the pipes, respectively, has been proposed. However, a flange fitter of such a clamp type connection unit may be deformed if it receives a high pressure, to thereby make fluid leak from the pipes.
FIG. 1 is a cross-sectional view of a conventional flange joint. It is difficult to form tapered screws at the joint portions of connection tubes 4 and 5 for medium-size or large-size pipes. Flange 10a having a predetermined width are respectively formed circumferentially at the ends of both the connection tubes 4 and 5, and a number of bolt holes 10d are mechanically worked on the flanges. A packing 10b is fitted between the flanges 10a in order to maintain air-tightness of the joint portions, and then the number of bolts 10c are tightened to connect the flanges with each other.
As described above, since the number of bolts 10c are tightened in the case of the flange joints, it consumes much working time to tighten the bolts. Further, during tightening the bolts 10c, they may be worn or damaged. Further, the width of the flanges 10a should be widened in order to tighten the bolts 10c, to thus cause weight of the piping materials to be increased. In addition, since a number of bolt holes should be mechanically worked in the flanges, a productivity of the flange joints is reduced and a manufacturing cost thereof is increased.